Caged fasteners such as caged nuts are frequently used in the manufacture of automobiles and other goods. A caged nut generally comprises a nut encaged in a structure that allows access to the nut bore, and provides the nut with a limited range of movement within the cage. In the manufacture of automobiles using caged nuts, the cage is welded onto the frame of the automobile and provides a nut at a selected location for the attachment of another part, such as a door, to the frame. The range of movement of the nut in the cage is provided so that the part being mounted on the frame may be adjusted relative to the frame during final assembly.
A caged nut provides advantages in that it can be assembled into a product framework during manufacture, so that the number of operations required in the final assembly of the product are reduced. In addition, a caged nut can be attached to the framework in locations which subsequently become enclosed or tightly circumscribed as more parts are assembled onto the product. If a caged nut was not provided in such situations, it would be very difficult to locate a nut by hand to receive a bolt used to fasten components such as a door onto a vehicle frame. In the usual practice in the automotive industry, the caged nut is spot welded on the frame prior to the application of rust inhibiting coatings and paint.
It has been found that welding the caged nut onto the frame can promote corrosion of the frame, since the rust inhibiting coatings may not penetrate into the space between the cage and the frame, thereby leaving bare metal parts which are suceptible to corrosion. Also, since the caged nut is attached to the frame before painting, the threading of the caged nut very often becomes clogged with paint during the painting operation, making it difficult to thread a bolt into the caged nut. Various methods proposed to solve this latter problem have included applying coatings of polytetrafluoroethylene (Teflon) to the threading in the cage nut, and inserting sleeves into the nut to protect the threads during the painting operation. However, these methods are both time-consuming and expensive.